The fruit of Cucurbitaceae plants contains a series of compounds called mogrosides which are glycosides of mogrol as a triterpene phytosterol. These mogrosides have the degree of sweetness several hundred times that of sucrose and have good quality of taste; thus, they are expected as alternative sweeteners for reduced-calorie foods like rebaudioside as a glycoside of a diterpene steviol in Asteraceae stevia.
For rebaudioside in stevia, rebaudioside A (a glycoside with 4 glucose residues added) and rebaudioside D (a glycoside with 5 glucose residues added), which are highly glycosylated, are estimated to be good in taste and have a high degree of sweetness. Similarly, for mogrol, one with 5 glucose residues added called mogroside V is good in sweetness and quality of taste and commercially available (Non Patent Literature 1). In addition, it is reported to have useful functionality other than that as a sweetener and is a plant metabolite receiving attention (Non Patent Literature 2). Meanwhile, it is unclear how a mogrol glycoside is biosynthesized in a plant body such as Siraitia grosvenorii. 